Given the task definition and input, reply with output. You are given a sentence and a question in the input. The information provided in the sentence should be enough to answer the question. You're expected to write the correct answer. Do not use any facts other than those provided in the sentence.

Sentence: It's not easy to be friends with a lion, but a friendship takes time and a lot of hard work and that's what is most important!. 
Question: What is so important to make a friendship last a long time?

hard work.